Polyurethanes are widely known as cushions, pillows, sofa, suitcase, soundproof material. Since polyurethanes do not provide heat-resistant property, the users mix polyurethanes with halogen-included compound, phosphoric compound, organic compound or inorganic compound to increase the fire-resistant effect thereof. However, all of fire-resistant agents used are water soluble and will dissolve in water. Therefore, the product produced lacks the fire-resistant property.